Composite wood and concrete construction



Dec. 3, 1935. J. F. SEILER COMPOSITE WOOD AND CONCRETE CONSTRUCTION Filed May 10, 1933 2 Sheets-Sheet 1 I Iwwenior:

J1? Seiler, m

Dec. 3, 1935. J. F. SEILER COMPOSITE WOOD AND CONCRETE CONSTRUCTION l Filed May 10, 1933 2 Sheets-Sheet 2 Patented Dec. 3, 1935 UNITED STATES COMPOSITE WOOD AND CONCRETE CONSTRUQII QN James F. Seiler, Washington, D. 0.

Application May 10, 1933, Serial No. 670,367

23 Claims.

The invention relates to the economical, efiicient use of wood and concrete combined in such a way as to properly employ the advantages of both materials. It may be employed in the manufacture of beams, girders and the like as well as in decks, floors, bridges, wharves, piers and in general in any position in which lasting strong material resistant to stresses and to wear or deterioration is desirable.

While not exclusively confined thereto the advantages of the invention are best brought out when wood properly preserved with creosote or salts is used. Of course wood appropriately treated to make fireproof may also be employed.

By the use of the invention the effect of lumber of large dimensions in cross section or in length or in both may be accomplished by the use of smaller or shorter pieces of wood which are more generally available and more economical to handle and transport as well as lower in cost. This is particularly so with respect to treated lumber since the difliculties and costs incident to treating large pieces of lumber may be very great.

As a specific illustration of the invention a wooden structure may be formed as the base. This may consist of suitable pieces of lumber preferably placed on edge and fastened together by spikes or other suitable means. Random lengths of lumber may be used and each of the edgewise pieces of lumber may be lengthened out by placing at its end a similar piece and so building up a unitary laminated structure of whatever length or width may be desired. In constructing the laminated structure preferably alternate laminations will be raised forming extended troughs therebetween. A layer of concrete of suitable depth may be poured upon the wooden base. The longitudinal troughs may form seats for keys of concrete to prevent the concrete from lateral displacement under stress. The longitudinal and lateral stress may be distributed by the more or less solid uniform concrete layer throughout the entire area or width of the structure, the greatest stress of course occurs at the bottom edge where the laminated wood occurs. In order to make the structure stronger laterally at this point there may be placed across the bottom at suitable points straps crossing the laminations and, if desired, extending from side to side of the structure, provided with suitable means for attachment to the laminations either with or without stress distributing means to be inserted between the larninations. In order to assist in holding the cement'top more firmly in place and prevent any sliding thereof with respect to the underlying wood and also to aid in the distribution of the load there may be placed in the longitudinal troughs, and before the cement is poured, transverse shear developers which preferably will engage the laminations at the bottom of the troughs and also may engage the laminations at both sides of the trough and extend thereabove so as to go beyond the natural line of cleavage or least resistance of the cement when poured. An important advantage of the longitudinal grooves is that they provide ready and efficient seats for the shear developers which placed therein are thoroughly and well anchored and efiiciently resist bending. The stresses developed and borne by each shear developer so arranged may be calculated and a suflicient number may be specified-in advance and installed. Since the chief function of these shear developers has to do with the longitudinal stress it may be convenient to particularly position the shear developers with respect thereto. Thus at each side of the center of stress they may be inclined toward the center in order to act more efiiciently and meet the stress more directly. These oppositely inclined shear developers may aid in preventing the cement leaving the wood in a vertical direction also.

If desired a somewhat similar structure may be built up by providing a pair of such wooden foundations with their sides containing the troughs facing eachother and placing a layer of cement or concrete between.

A tool especially adapted for providing seats for the shear developers is also contemplated.

Various phases of the invention will appear from the description of the accompanying drawings in which Figure 1. is a side elevation of a longitudinal section of a flooring illustrating the invention. Fig. 2 is a fragmentary transverse vertical section on the line 2--2 of Fig. 1. Fig. 3 is a fragmentary plan view of a portion of the under portion of the structure. Fig. 4 is a. longitudinal vertical section on the line 4-4 of Fig. 3. Fig. 5 is a fragmentary transverse vertical section on the line 5-5 of Fig. 4 somewhat enlarged in scale. Fig. 6' is a transverse vertical section of a plurality of structures made up of cement associated with two series of wooden laminations in position for use. Fig. 7 is a vertical section on the line 1-1 of Fig. 6. Fig. 8 is a transverse vertical section somewhat enlarged showing the structure of Fig. 6 in position for pouring the cement. Fig. 9 is a transverse vertical fragmentary'section showing an alternative arrangement of the wooden laminations. Figs. 10 and 11 are front and side elevations of a tool which may be conveniently employed for providing seats for the shear developers, and Fig. 12 is a fragmentary view of an optional element.

Resting on suitably spaced supports 20 and 2| in the drawings is a longitudinally laminated structure 22 consisting of a plurality of boards or timbers 23 and 24. As illustrated the boards 23 are wider than the boards 24 and they are all set upon edge. While not essential they have been illustrated as of the same thickness. The timbers are preferably treated with a suitable preservative in the manner well known to the art before being assembled but untreated wood .might be used. The type of character of preservative is not essential but may consist of creosoting or metallic salt impenetration. The timbers are preferably dressed so that they may fit tightly and evenly against each other and the laminated fabric is made up by fastening the various boards together by means of nails or spikes 25 or in any other suitable manner. Each longitudinal timber 23 or 24 may be of any suitable length. Preferably the timbers are made as long as the structure to be manufactured by adding boards or timbers at their ends. In the drawings vertical splices 26 are shown for convenience and economy but splices of any other character may be employed. The boards making up the individual timbers may be of random length as may be most economically procured or they may be of regular length but their arrangement in the laminated structure preferably will be such that the splices 26 will be staggered and overlapped by adjacent boards, the location of the splices preferably being such as to properly develop the strength of the structure. Preferably the ends of the boards should be neatly fitted in the splices 26. It will be observed that this arrangement may make a sturdy relatively rigid construction extending throughout the entire structure.

The alternate timbers 24 being narrower vertically than the adjacent timbers 23 provide longitudinal grooves in the surface of the laminated structure. Into the laminated grooves at suitable points may be placed shear developers for transmitting and distributing the strains presently to be considered. The shear developers will preferably consist of triangular pieces of metal 21 shown somewhat enlarged in Fig. 5.

In Figs. 10 and 11 is shown a tool 28 having a handle 29. The tool 28 is substantially the same size and shape as the shear developer 21 and is sharpened at its two edges 30. Of course each shear developer might be sharpened on its edges and driven into its appropriate seat in the channels 3! above the narrower timbers 24 and between the wider timbers 23. The expense of preparing and sharpening the shear developers 21, however, would be relatively large and I therefore prefer to place the tool 28 at appropriate spots in the structure and give the handle 29 a blow so as to cut a seat for the shear developers 21 in the sides of the channel 3| and also 'in the bottom of the channels 3|. When the tool 28 is removed the shear developers may be placed in their seats and driven further home, insuring a rigid close grasp in the wood members.

In Fig. 5 is shown an enlarged fragmentary view of a shear developer 21 in position. It will be observed that the downwardly projecting tip of the shear developer enters the edge of the narrower timber 24 and the two sides 46 and 41 shear developer 21 which is in engagement with the three timbers may be calculated and adjusted so as to determine the stress which may be transmitted by the shear developer from the concrete into the wood. This arrangement as controlled by the tool 28 driven in to form the seat for the shear developer makes it possible to calculate in advance the stresses which may be transmitted by them and accordingly the stresses to which the completed structure may be put safely.

When the shear developers have been put in place a suitable surface coating such as concrete or cement 32 may be poured upon the laminated wood fabric. This will enter the channels 3| and engage the shear developers 21 and so be pre vented from slipping or sliding in any direction. Because the cement slab is solid and rigid any strains or stresses caused by superincumbent weights will be distributed through the grooves 3| and shear developers 21 more or less uniformly throughout the entire structure. Weight placed midway between the supports 20 and 2| structure of this invention, however, including the shear developers, the longitudinal strain, especially tension, will be largely upon the lower edge of the timbers making up the fabricated structure. Because wood is very considerably stronger than cement and because it is very much lighter, the present construction in which the wood and cement are so intimately associated as to form practically a unitary stress member is highly economical to construct, is relatively light and requires a minimum of supporting structure to carry it. It is to be noted that there are no longitudinal stringers necessarywith the present construction but the laminated wood and concrete fabric has in itself sufiicient strength to carry strains placed upon it.

The spikes 25 used to fasten the laminations together may be suificient to distribute and carry whatever lateral strains may be placed upon the structure, but it may be convenient to provide at suitable intervals transverse straps 33 placed across the bottom of the structure. These straps may be of wood, preferably treated, and put in place on the bottom after the laminated structure has been built up in position. When the laminated structure is made up and assembled a strap 33 may be temporarily placed in position and suitably marked to indicate occasional separations or joints between the boards'making up the laminated structure. A saw or other suitable instrument may be employed for making kerfs in the strap 33 corresponding with the positions of the joints in the laminations. In the keri's may be seated shear developers 21. The shear developers 21 preferably will be inserted so that their points extend upwardly and the straps 33 may be then placed in position below the laminated structure so that the points of the various shear developers enter between the laminations and then the entire strap carrying the shear developers 21 driven upward to contact with the lower side of the fabricated structure to the position shown in Fig. 2 where'the shear developers have entered between the layers of the fabricated structure so as to equalize and distribute the load transversely. Of course the straps 33 may be additionally held in position by means of bolts or spikes 34. By this construction much of the transverse strain is applied longitudinally to the cross straps 33.

While a satisfactory construction can be made by employing boards 23 of uniform width, when desired, the upper edges of'the projecting boards 23 may be apertured as indicated at 35 in Fig. 12.'

This construction may be somewhat more expensive but may be more effective for some purposes.

In Fig. 9 is shown an arrangement in which the wooden fabricated structure is made up of a series of alternate boards 36 which have between them boards 3| which extend somewhat above the upper edges of the boards 36 but do not come entirely to the bottoms of the boards 36. The alternate boards may be of equal or different widths. This arrangement saves considerable lumber and may be more effective for some uses. If in the arrangement shown in Fig. 2 the boards 23 are 2x10 inches for instance, and the boards 24 are 2x8 inches for instance, the layer. of concrete 32 may be 4 inches for instance, giving the effect of a 14 inch beam. In the arrangement in Fig. 9, however, the members 35 may be 2x10 and the members 31 may be 2x8 or 2x6 arranged to project two inches above the tops of the members 36. when on this is put a layer of 4-inch concrete such as 32, there is produced the effect of a 16-inch beam with less or no more wood and cement than in the previously described 14-inch beam effect.

In view of the fact that the longitudinal strength of wood is very considerably more than the strength of the concrete it may be that by the arrangement in Fig. 2 which causes all of the wooden members to come to the bottom of the structure, more strength is produced at the bottom than is needed. By the arrangement in Fig. 9 only one half as much wood is provided at the bottom of the structure as by the arrangements illustrated in Fig. 2. This reduced amount of wood may ordinarily be suflicient to bear the strains imposed at the bottom as limited by the cement surface. In view of the fact that there are channels left below the members 31 in Fig. 9 the cross strap 33a instead of being provided with the shear developers 2! may be cut out on its upper surface leaving projections 38 to engage the channels or may have fastened upon or set into it blocks 39 to enter into and engage the channels.

The shear developers are illustrated in the form of equilateral triangles but this is not essential as various other triangular or other forms may be employed to engage the wood and concrete. The material of which the shear developers is made may be selected to meet various conditions of cost, durability and stress involved. Preferably they will be made of metal including such strong material as steel, wrought iron or steel alloys and of a size and thicknem which may be suitable for the particular condition involved.

In view of the fact that timber as delivered may come of somewhat varying thickness, it is possible that in a long structure made upof spliced laminations the grooves 3| may not be straight but may waver somewhat in contour. This may not be fatal to the invention or. indeed may be advantageous as forming an irregular grasp on the concrete. Nevertheless the timbers employed in the construction will preferably be dressed to approximately uniform thickness thus. giving better, closer fits in the various timbers especially at the splices wherethis is more important.

The composite structure will ordinarily contain within itself in the laminated structure sufficient wood to support the workmen and machinery involved in the installation and pouring 10 of the cement surface and since the cement is poured directly upon the laminated wood structure no construction supports, posts or frames are needed. It will be observed that there is produced a construction having great strength for its weight and having a rigid, hard-wearing surface for trafllc, whether of foot or vehicles.

The invention produces a construction of ,vertical laminations of wood of the same or different depths forming grooves on the top surface of the wood operating to bind the concrete top to the wood thus forming a composite structure the two materials acting together as a single stress member, especially in view of the metal shear developers which are driven into the tops and sides of the laminations to prevent slippage between the concrete and wood when beam action or bending stress is developed, the laminated pieces of wood being so proportioned and placed as to develop the maximum strength and stiffness of the two materials making up the composite s ructure. The concrete top also acts as a pro-- tection from weather to the underlying laminated wood structure thus tending to afiord a permanent construction free from the expense of frequent repairs.

The construction may be of any desired length or of any desired width depending upon the number and size of laminations employed.

When the structure is installed as a flooring in a building the underside of the laminated structure may be exposed unfinished or may be painted or have applied to it or suspended from it any suitable plastering or other desired ceiling material.

It may be desired to fabricate separate units and place them in appropriate positions for use. Such an arrangement is especially indicated in Figs. 6, 7 and 8. A plurality of laminated fabrics of wood similar to that already described may be formed of a suitable length and width. A pair of such laminated structures after being provided with suitable shear developers 2'! may be placed on their sides as indicated in Fig. 8 with their channel sides facing each other and a suitable distance apart. Cement or concrete 40 may then be poured between the members fastening them together and finally setting into a unit. Projecting from the fabricated members may be bolts 4| provided with collars or washers 42 at their heads to produce additional anchorage in the concrete and reinforcement for the structure as a whole. Tongues 43 and grooves 44 may be formed in the respective sides of the elements so that when they are placed side by side as illustrated in Fig. 6 they may interlock.

Since the concrete 32 enters into the grooves or channels above the members 24 there is a natural line of weakness or cleavage in the concrete at the upper edge of the members 23. It will be noted, however, that as shown more clearly in Fig. 5 the shear developers 21 are arranged so that they project above the upper edges of the timbers 23 and into the cement 32 beyond this 75 line of weakness thus transferring the stress directly from the body of the cement into the wood and insuring a better and stronger construction of the combined member.

Ordinarily it may be found desirable to use a surface layer of concrete made by the use: of Portland cement but other types of concrete may be used when desired or convenient and where the terms concrete or cement are used in the claims they are to be taken in the broader sense as relating to any suitable concrete however produced.

Theproportions described and illustrated may make the substance of the invention clear but are not essential to the invention. The forms, shapes, arrangements, proportions and sizes of the various elements may be suitably varied without departing from the invention.

I claim as my invention:

1. A composite construction comprising a laminated wood base made up of contacting vertical laminations of preserved wood each made up of a plurality of boards placed end to end the joints in the various laminations overlapping and alternate laminations having edges at different levels, triangular metallic shear developers inserted between projecting laminations and engaging them and the intermediate lamination each shear developer being inclined in an appropriate direction, a layer of concrete on the face of the wood base and engaging and enveloping the shear developers, a transverse strap across the free edge of the laminations and shear developers between the laminations and engaging the strap.

2. A composite construction comprising a land-- nated wood base made up of contacting vertical laminations of preserved wood each made up of a plurality of boards placed end to end the joints in the various laminations overlapping and alternate laminations having edges at different levels, triangular metallic shear developers inserted between projecting laminations and engaging them and the intermediate lamination each shear developer being inclined in an appropriate direction, a layer of concrete on the face of the wood base and engaging and enveloping the shear developers and a transverse strap across the free edge of the laminations.

3. A composite construction comprising a laminated wood base made up of contacting vertical laminations of preserved wood each made up of a plurality of boards placed end to end the joints in the various laminations overlapping and alternate laminations having edges. at different levels, shear developers in the fact: of the laminated structure and extending thezebeyond each shear developer being inclined in in appropriate direction, a layer of concrete on the face of the wood base .and engaging and enveloping the shear developers, a transverse strap across the free edge of the laminations and shear developers between the laminations and engaging the strap.

4. A composite construction comprising a laminated wood base made up of contacting vertical laminations of preserved wood each made up of a plurality of boards placed end to end the joints in the various laminations overlapping and alternate laminations having edges at different levels, shear developers inserted between and engaging projecting laminations each shear developer being inclined in an appropriate direction, a. layer of concrete on the face of the wood base and engaging and enveloping the shear developers, a transverse strap across the free edge of the laminations and shear developers between the laminations and engaging the strap.

5. A composite construction comprising a laminated wood base made up of contacting vertical laminations of preserved wood each made up of a plurality of boards placed end to end the joints in the various laminations overlapp and alternate laminations having edges at different levels on both sides, triangular metallic shear developers inserted between projecting laminations and engaging them and the intermediate lamination, each shear developer being inclined in an appropriate direction, a layer of concrete on the face of the wood base and engaging and enveloping the shear developers, a transverse strap across the free edge of the laminations and means thereon for engaging the projecting edges of the laminations.

6. A composite construction comprising two series of longitudinal timbers laid on edge with lntermediate timbers of less height rigidly secured thereto and forming longitudinal channels in their faces, shear developers in the channels and engaging the adjacent timbers and projecting beyond the timbers and channels, the two series being arranged with their channel sides facing each other, cement between the two series and filling the channels of each and engaging all the shear developers and additional anchoring and reinforcing members projecting from the series into the cement.

'7. A composite construction comprising two series of longitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels in their faces, shear developers in the channels and engaging the adjacent timbers and projecting beyond the timbers and channels, the two series being arranged with their channel sides facing each other, and cement between the two series and filling the channels of each and engaging all the shear developers.

8. A composite construction comprising two series of longitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels in their faces, the two series being arranged with their channel sides facing each other, cement between the two series and filling the channels of each and anchoring and reinforcing members projecting from the series into the cement.

9. A composite construction comprising two series of longitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels in their faces, the two series being arranged with their channel sides facing each other, and cement between the two series and filling the channels of each.

10. A composite construction comprising longitudinal timbers laid on edge with intermediate timbers of less height secured thereto and forming longitudinal channels all secured together in continuous succession the timbers being made of a plurality of pieces laid end to end with staggered joints, shear developers in the channels engaging the timbers forming the channels and extending beyond the timbers and channels and cement on the face engaging the channels and the shear developers.

11. A composite construction comprising longitudinal timbers laid on edge with intermediate timbers having edges of less height secured .thereto and forming longitudinal channels all secured together in continuous succession the timbers being made of a plurality of pieces laid end to end with staggered joints, shear developers in the channels engaging the timbers forming the channels and extending beyond the timbers and channels, cement on the face engaging the channels and the shear developers, and a transverse strap across the free edge of the laminations.

12. A composite construction comprising longitudinal timbers laid on edge with intermediate timbers of less height secured thereto and forming longitudinal channels all secured together in continuous succession the timbers being made of a plurality of pieces laid end to end with staggered joints, transverse shear developers in the channels engaging the timbers forming the channels and extending beyond the timbers and the channels and cement on the face engaging the channels and the shear developers.

13. A composite construction comprising longitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels, shear developers in the channels and engaging the adjacent timbers and projecting beyond the timbers and out of the channels, and a layer of cement over the surface and filling the channels and engaging the shear developers.

14. A composite construction comprising longitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels, transverse shear developers in the channels and engaging the adjacent timbers and extending beyond the timbers and the channels and a layer of cement over the surface and filling the channels and engaging the shear developers.

15. A composite construction comprising longitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels, transverse metallic shear developers in the channels and engaging the adjacent timbers and projecting beyond the timbers and out of the channels, and a layer of cement over the surface and filling the channels and engaging the shear developers.

16. A composite construction comprising longitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels at both faces, shear developers in the channels at one face and engaging the adjacent timbers and projecting beyond the timbers and out of the channels, a layer of cement over the face filling the channels and engaging the shear developers, a strap across the other face and means thereon for engaging the projecting edges of the timbers.

17. A composite construction comprising longitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels at both faces, a layer of cement over the face filling the channels, a strap across the other face and means thereon for engaging the projecting edges of the timbers.

18. A composite construction comprising lon- 5 gitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels at both faces each timber made up of a plurality of boards placed end to end the joints of the various laminations overlapping, shear developers in the channels at one face and engaging the adjacent timbers and projecting beyond the timbers and out of the channels, a layer of cement over the face filling the channels and engaging the shear developers, a strap across the other face and means thereon for engaging the projecting edges of the timbers.

19. A composite construction comprising longitudinal timbers laid on edge with intermediate timbers of less height rigidly secured thereto and forming longitudinal channels at both faces, shear developers in the channels at one face and engaging the adjacent timbers and projecting beyond them, a layer of cement over the face filling the channels and engaging the shear developers, a strap across the other face and means integral therewith for engaging the projecting edges of the timbers.

20. A composite construction comprising longitudinal timbers laid on edge with the edges of alternate timbers extending beyond the others and rigidly secured together to form longitudinal channels, shear developers in the channels and engaging the adjacent timbers and extending beyond the timbers and out of the channels, and a layer of cement on the surface engaging the shear developers and filling the channels.

21. A composite construction comprising longitudinal timbers with their exposed surfaces separated from each other and secured together to form longitudinal channels, shear developers in the channels and engaging the timbers and extending beyond the timbers and out of the channels, and a layer of cement over the exposed surface and engaging the shear developers and filling the channels.

22. A composite construction comprising longitudinal timbers laid on edge, transverse shear developers extending from the edges of the timbers and beyond the area enclosed by the timbers, and a layer of cement engaging the edges of the timbers and the shear developers.

23. A composite construction comprising longitudinal timbers laid on edge, transverse diverse- 1y inclined shear developers extending from the edges of the timbers, and a layer of cement engaging the edges of the timbers and the shear developers.

JAMES I". SEE-ER. so 

